Persist light client updates (#5545)

* persist light client updates

* update beacon chain to serve light client updates

* resolve todos

* cache best update

* extend cache parts

* is better light client update

* resolve merge conflict

* initial api changes

* add lc update db column

* fmt

* added tests

* add sim

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into persist-light-client-updates

* fix some weird issues with the simulator

* tests

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into persist-light-client-updates

* test changes

* merge conflict

* testing

* started work on ef tests and some code clean up

* update tests

* linting

* noop pre altair, were still failing on electra though

* allow for zeroed light client header

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into persist-light-client-updates

* merge unstable

* remove unwraps

* remove unwraps

* Update light_client_update.rs

* merge unstable

* move functionality to helper methods

* refactor is best update fn

* refactor is best update fn

* improve organization of light client server cache logic

* fork diget calc, and only spawn as many blcoks as we need for the lc update test

* fetch lc update from the cache if it exists

* fmt

* Fix beacon_chain tests

* Add debug code to update ranking_order ef test

* Fix compare code

* merge conflicts

* fix test

* Merge branch 'persist-light-client-updates' of https://github.com/eserilev/lighthouse into persist-light-client-updates

* Use blinded blocks for light client proofs

* fix ef test

* merge conflicts

* fix lc update check

* Lint

* resolve merge conflict

* Merge branch 'persist-light-client-updates' of https://github.com/eserilev/lighthouse into persist-light-client-updates

* revert basic sim

* small fix

* revert sim

* Review PR

* resolve merge conflicts

* Merge branch 'unstable' into persist-light-client-updates

testing/ef_tests/src/handler.rs

@@ -837,6 +837,32 @@ impl<E: EthSpec + TypeName> Handler for KzgInclusionMerkleProofValidityHandler<E
     }
 }
 
+#[derive(Derivative)]
+#[derivative(Default(bound = ""))]
+pub struct LightClientUpdateHandler<E>(PhantomData<E>);
+
+impl<E: EthSpec + TypeName> Handler for LightClientUpdateHandler<E> {
+    type Case = cases::LightClientVerifyIsBetterUpdate<E>;
+
+    fn config_name() -> &'static str {
+        E::name()
+    }
+
+    fn runner_name() -> &'static str {
+        "light_client"
+    }
+
+    fn handler_name(&self) -> String {
+        "update_ranking".into()
+    }
+
+    fn is_enabled_for_fork(&self, fork_name: ForkName) -> bool {
+        // Enabled in Altair
+        // TODO(electra) re-enable once https://github.com/sigp/lighthouse/issues/6002 is resolved
+        fork_name != ForkName::Base && fork_name != ForkName::Electra
+    }
+}
+
 #[derive(Derivative)]
 #[derivative(Default(bound = ""))]
 pub struct OperationsHandler<E, O>(PhantomData<(E, O)>);